Printable Version of Topic

Posted by: Porschef May 22 2020, 10:55 AM

A couple weeks back I hit some real rough road on my way home from my mechanic neighbor’s shop. The car started running out of power, I made it another couple hundred feet before it died. With help from said neighbor we were able to push it down the road to a safe spot, where Hagerty towing picked it up.

I have a fuel pressure gauge in the engine bay, whenever I would engage the pump it would build up pressure and immediately fall to zero. I thought I had a bad injector or maybe the cold start valve failed, so I pulled them all individually and checked them; they were all leaking. A Noid light showed them all to be open. WTH? My neighbor suspected the ECU, but based on what I’ve read they rarely fail.

Anyway everything else seemed ok so I put out a WTB and Jim Hoyland responded with a unit and an offer to check it out and then buy it if it worked . So last evening I pulled the harness off the one in the car and plugged it into the new one. Presto! Pressure held right where it should. A quick experiment putting the harness back into the old one got the same previous result. So I’m pretty confident that the problem has been resolved.

As much as I wanted to start it, I did not based on the oil reeking of gas. So I’ll do a change, and see what happens.

Big thanks to Jim for helping out, it’s a great community.

Posted by: 914Sixer May 22 2020, 11:06 AM

Looks like you fall into the 10 % group for ECU failure. 90 % of the time it is a brittle wire harness and bad connections. You might have some loose parts in the ecu itself. Vibration got to some on the solder joints.

Posted by: Porschef May 22 2020, 11:47 AM

Yes, I agree. I may open it up just for kicks. But with all 4 injectors dumping fuel I figured it had to be the brain.

The brain...

Posted by: ClayPerrine May 23 2020, 08:18 AM

If you open it up, you will find there is no "Brain" to speak of. No processor, no integrated circuits, just a bunch of big transistors, resistors, capacitors and inductors.
Just big, over engineered durable parts. I would guess that one of the caps failed due to age.

Posted by: rgalla9146 May 23 2020, 11:04 AM

That's great news Joe.....you were right all along !
I would have that old one open in about a minute. I'd be so curious.

Posted by: jim_hoyland May 23 2020, 04:31 PM

Great news ! Good thing you were not 400 miles down the road... Honest, you are the first 914 owner I know of that lost their brain; it would be very cool to do a post-mortem.
Seems like Spoke revised a set up to diagnose the ECU

Posted by: TheCabinetmaker May 23 2020, 05:01 PM

I've had one fail. Lost the fuel pump circuit

Posted by: Porschef May 24 2020, 06:31 AM

Heading out to pick up some oil and get it changed. Will report back later.

Posted by: JFJ914 May 24 2020, 12:57 PM

Me too, twice

Posted by: Porschef May 24 2020, 03:34 PM

Ok, happy to report its back up and running. Props to Jim Hoyland for his generous offer and expeditious action, what a great asset to this community. Thanks Jim!

I changed the oil and got it to start, albeit with a couple snags. But got it to run, was definitely running rich by the white smoke and high readings on the A/F ratio gauge. So not only was I able to dial back the static but also the spring on the “barn door”, and the idle mixture.

A few adjustments later and it’s running really well. It seems to be happier with a slightly leaner mixture. It’s like a black science, figuring this stuff out. Itinerant Air is a great resource also.

Happy and Reflective Memorial Day to all.

I’m gonna take a drive.

Posted by: Big Len May 24 2020, 04:09 PM

Get out there. Good job.

Posted by: StarBear May 24 2020, 07:20 PM

Hooray! Great job! These cars are a bit finicky, but once they get dialed in they're such a pleasure to drive (and hear).

Posted by: Porschef May 26 2020, 06:58 AM

So I opened up the ECU (two screws on the rear allow the guts to slide out of the case) but didn’t see anything obviously wrong with it.

I didn’t go much further than that.

Kinda reminded me of Electronics shop, circa 1973...

Posted by: pt_700 May 26 2020, 12:59 PM

me too, also...